Super Insulation Do's and Dont's and learning as you go

The Super Insulation Building Revolution, started in the 1970's has gone through fits and starts, but one thing that is a constant throughout. It is a movement where building science reigns. As with any discipline where science is used as the basis but the practitioners are not scientists, the application produces good results and ok results and bad results. It is a learning process. Not just in what you build as a builder or architect, but in what tools you use to design and construct the building.

As a designer/consultant in the Super Insulated Building community in Vermont I have been working for years to understand how buildings work. I'm not a scientist. I'm not in the field designing experiments and correlating data and analyzing the results. I'm in an office working on designs, trying to design the energy use of a building so that it is as low as it can be within the constraints of site location, client desires and budget. In the process I am also trying to make sure that the homes I help design are durable. That they will perform not just thermally but that they will be healthy, safe and last for a very long time without material failure.

The tools available to help me discern the expected durability of a wall construction are varied. I am leaning on the shoulders of great building scientists who are in the field doing that work. John Straube, Joe Lstiburek, Peter Yost, Alex Wislon, just to name a few. These scientists and their peers are producing the information we need as designers, architects and builders to do our best.

Only by constantly studying their work, going to seminars given by them and generally keeping up with the developments in the field can we learn the Do's and Dont's that govern good building design.

Yet there is a rub there. My friend and colleague, Jim Bradley of Caleb Construction in Cambridge, Vermont has said to me on many occasions,"I go to the conferences and listen to the experts and it seems that every year their advice changes. The perfect wall is perfect that perfect changes."  Jim is absolutely right. Building science is changing all of the time. The themes stay the same. What we learn is updated as we continue to learn what is right. What works, what doesn't.  As we change the types of construction we are using, the intricacies of how these walls, floors and roofs operate, independently and in conjunction with one another changes.

"We are experimenting, building experiments with each new design." This loose quote is from a PH Builder Trainer at a recent builder training. It can be unsettling but it is the truth. The other truth is that all of the other builders in the country are also experimenting. We are all doing what we think is right. Some of us are focusing on houses as whole systems and we think that we are right. I happen to agree with this. I have been on energy audits and seen the rotting remains of walls and roofs that were built with what the builder considered to be proper building practices, yet the wall/roof failed.

In my opinion what we need to do is move forward with caution but still move forward. When we build a home and later find out that we might have done something questionable we need to stand up and say I think that might cause an issue in the future. Let's go and take a look at this to see if my concerns are justified.

Furthermore, we need to learn and keep in mind the abilities and the limitations of the models we are using. Any modeling software can only give you good advice/information if you know its abilities and limitations. We need to be properly trained in the use and inputs for these programs and also in how far the information we get from them can be applied to our designs.


Forward and upward for sure, but with eyes wide open.

Chris West

Next steps

You would think that it is easy to finish off a project like this. Yet when you are doing lots of the work yourself and you don't mind a bit of a mess it can drag on!

We are now having the drywall installed in the basement. Has to be done in two parts due to the fact that we are living in the house during the renovation and are using these spaces. One space needs to be made empty to allow for work, filling the other with stuff. The empty space gets sub floor, sheetrock, paint, floor, trim, installed cabinets/etc. and then move all of the stuff from the other room into the finished space to allow for the unfinished space to get finished.

This while doing all of the regular work of life.

I am working on an analysis of the energy use of the house this past winter. It was quite the winter. It looks like we spent around $800 to heat the house for the heating season. We would have spent more than $4000 to heat the house before the retrofit. I'll have hard numbers on what we used soon and projecting it to what it would have cost before the retrofit will be difficult.

This heating season so far had 8200 Heating Degrees Days. The usual Vermont winter is 7200 HDD. That is a 13.8% increase! It's not over yet either. Yesterday's nighttime low was 25 F. Last night it was in the upper 30's.

Fortunately the house doesn't really need heat if it is above 40F and it is sunny out. The solar heat gains are enough to heat the house to 70F+ and the super insulation will keep it warm through the night.

If it is not sunny then we do have to put the heat pump on.

I will be submitting the house to the Thousand House Challenge, but need to get a year's worth of data first (November to November).

Still not certain if we are going to go forward with one heat pump or if we might add one smaller one in one of the upstairs bedrooms to make sure we have enough heat.